Qt: Debugger console history

CHANGES

@@ -130,6 +130,7 @@ Misc:
  - GB: Improved SGB2 support
  - Libretro: Reduce rumble callbacks
  - Debugger: Minor text fixes
+ - Qt: Debugger console history
 
 0.7 beta 1: (2018-09-24)
 - Initial beta for 0.7

src/platform/qt/DebuggerConsole.cpp

@@ -17,6 +17,8 @@ DebuggerConsole::DebuggerConsole(DebuggerConsoleController* controller, QWidget*
 {
 	m_ui.setupUi(this);
 
+	m_ui.prompt->installEventFilter(this);
+
 	connect(m_ui.prompt, &QLineEdit::returnPressed, this, &DebuggerConsole::postLine);
 	connect(controller, &DebuggerConsoleController::log, this, &DebuggerConsole::log);
 	connect(m_ui.breakpoint, &QAbstractButton::clicked, controller, &DebuggerController::attach);
@@ -36,7 +38,47 @@ void DebuggerConsole::postLine() {
 	if (line.isEmpty()) {
 		m_consoleController->enterLine(QString("\n"));
 	} else {
+		m_history.append(line);
+		m_historyOffset = 0;
 		log(QString("> %1\n").arg(line));
 		m_consoleController->enterLine(line);
 	}
 }
+
+bool DebuggerConsole::eventFilter(QObject*, QEvent* event) {
+	if (event->type() != QEvent::KeyPress) {
+		return false;
+	}
+	if (m_history.isEmpty()) {
+		return false;
+	}
+	QKeyEvent* keyEvent = static_cast<QKeyEvent*>(event);
+	switch (keyEvent->key()) {
+	case Qt::Key_Down:
+		if (m_historyOffset <= 0) {
+			return false;
+		}
+		--m_historyOffset;
+		break;
+	case Qt::Key_Up:
+		if (m_historyOffset >= m_history.size()) {
+			return false;
+		}
+		++m_historyOffset;
+		break;
+	case Qt::Key_End:
+		m_historyOffset = 0;
+		break;
+	case Qt::Key_Home:
+		m_historyOffset = m_history.size();
+		break;
+	default:
+		return false;
+	}
+	if (m_historyOffset == 0) {
+		m_ui.prompt->clear();
+	} else {
+		m_ui.prompt->setText(m_history[m_history.size() - m_historyOffset]);
+	}
+	return true;
+}

src/platform/qt/DebuggerConsole.h

@@ -21,8 +21,13 @@ private slots:
 	void log(const QString&);
 	void postLine();
 
+protected:
+	bool eventFilter(QObject*, QEvent*) override;
+
 private:
 	Ui::DebuggerConsole m_ui;
+	QStringList m_history;
+	int m_historyOffset;
 
 	DebuggerConsoleController* m_consoleController;
 };